From 50bd0592b6d28a532ab5bd9eb58d2e3ada8edcdb Mon Sep 17 00:00:00 2001
From: Jason Smart <jlsmart@meta.com>
Date: Sat, 21 Dec 2024 21:16:05 -0800
Subject: [PATCH] Added initial support for BQ HLL functions

Signed-off-by: Jason Smart <jlsmart@meta.com>
---
 .../dialect/standardsql/dialect_functions.ts  | 36 +++++++++++++++++++
 .../src/dialect/standardsql/standardsql.ts    |  1 +
 2 files changed, 37 insertions(+)

diff --git a/packages/malloy/src/dialect/standardsql/dialect_functions.ts b/packages/malloy/src/dialect/standardsql/dialect_functions.ts
index b2f08dfd4..33be2308d 100644
--- a/packages/malloy/src/dialect/standardsql/dialect_functions.ts
+++ b/packages/malloy/src/dialect/standardsql/dialect_functions.ts
@@ -10,8 +10,12 @@ import {
   DefinitionBlueprint,
   DefinitionBlueprintMap,
   OverloadedDefinitionBlueprint,
+  TypeDescBlueprint,
 } from '../functions/util';
 
+// Cute shortcut So you can write things like: {array: T} and {dimension: T}
+const T: TypeDescBlueprint = {generic: 'T'};
+
 const date_from_unix_date: DefinitionBlueprint = {
   takes: {'unix_date': 'number'},
   returns: 'date',
@@ -69,6 +73,38 @@ export const STANDARDSQL_DIALECT_FUNCTIONS: DefinitionBlueprintMap = {
   date_from_unix_date,
   string_agg,
   string_agg_distinct,
+  hll_accumulate: {
+    default: {
+      takes: {'value': {dimension: T}},
+      returns: {measure: {sql_native: 'bytes'}},
+      generic: {
+        'T': ['string', 'number'],
+      },
+      isSymmetric: true,
+      impl: {function: 'HLL_COUNT.INIT'},
+    },
+  },
+  hll_combine: {
+    takes: {'value': {sql_native: 'bytes'}},
+    returns: {measure: {sql_native: 'bytes'}},
+    impl: {function: 'HLL_COUNT.MERGE_PARTIAL'},
+    isSymmetric: true,
+  },
+  hll_estimate: {
+    takes: {'value': {sql_native: 'bytes'}},
+    returns: {dimension: 'number'},
+    impl: {function: 'HLL_COUNT.EXTRACT'},
+  },
+  hll_export: {
+    takes: {'value': {sql_native: 'bytes'}},
+    returns: {dimension: {sql_native: 'bytes'}},
+    impl: {sql: 'CAST(${value} AS BYTES)'},
+  },
+  hll_import: {
+    takes: {'value': {sql_native: 'bytes'}},
+    returns: {dimension: {sql_native: 'bytes'}},
+    impl: {sql: 'CAST(${value} AS BYTES)'},
+  },
   ...def('repeat', {'str': 'string', 'n': 'number'}, 'string'),
   ...def('reverse', {'str': 'string'}, 'string'),
 };
diff --git a/packages/malloy/src/dialect/standardsql/standardsql.ts b/packages/malloy/src/dialect/standardsql/standardsql.ts
index 7ea2dcdff..309504cc0 100644
--- a/packages/malloy/src/dialect/standardsql/standardsql.ts
+++ b/packages/malloy/src/dialect/standardsql/standardsql.ts
@@ -126,6 +126,7 @@ export class StandardSQLDialect extends Dialect {
   cantPartitionWindowFunctionsOnExpressions = true;
   hasModOperator = false;
   nestedArrays = false; // Can't have an array of arrays for some reason
+  supportsHyperLogLog = true;
 
   quoteTablePath(tablePath: string): string {
     return `\`${tablePath}\``;